Where are the coolant drain plugs on the GM 350 engine block?

[William Perry]

I've been pulling my hair out here, guys. I am ready to change out my head gaskets and I'm under the truck all day and can't find those drain plugs. By the way, I have a 88' GMC Sierra 5.7L(K1500).

Here's what I've read: There are two drain plugs, one on each side of the block, near the middle of the engine where the oil pan meets the engine. I really like my Hanes manual, but sometimes that book can be pretty vague about the important things. A sentence worth of description, and no pictures at all(Of course I embellished a little in the sentence above, the manual didn't even say THAT much..)

The only thing that remotely looks like a plug is the knock sensor(right where one of the drain plugs actually should be, according to the description). The only things I can see under there is the knock sensor on the passengers side, and one of the freeze plugs on the drivers side.

I heard through the grapevine that if you pull the knock sensor, it will drain the coolant. Well I'm afraid if I drain that one, it will only drain that half of the block. Not sure if there is one or two.

So can you help me out? Maybe give a better description of where the plugs may be or maybe even send a link to a picture?

Thanks

 

[T B]

You know how to change head gaskets but don't know how to drain the antifreeze??

The drain plug is on the drivers side of the radiator. You dont have to drain very much to get the level below the intake and heads.